.feedback-content {
  background-image: url('https://xtbs.ljsyy.net/wxamp-app-background-image.png');
  background-repeat: no-repeat;
  background-attachment: fixed;
  background-size: 100% 100%;
  -webkit-backdrop-filter: blur(6px);
  /* 背景图垂直、水平均居中 */
  background-position: center center;
  height: 97vh;
}